I have two complete board sets. Atari Sys1 and RoadBlasters cart. Also a new A/R board.
One set (came with the cab), the sound does not work unless I bypass the power from transformer (transformer tests good all voltages) for the AR board straight to switching power supply. Also, the game seems to think the special Turbo (the one you catch from the plane) is always there and pressing the thumb buttons trigger turbo ON/OFF. Unless another special is truly active like laser for instance, the turbo is constanty switched on and off as if I have unlimited turbo even though I never caught the turbo special and the car will run at turbo without pressing the foot pedal. When the button is clicked turning turbo off, foot pedal is active again. Otherwise game runs well. Can't figure out why the game thinks i have turbo specail power all the time (it also does not show turbo at the bottom like it will when you actually have it).
Second set (donor cab), turbo is not the problem at all. Buttons all work perfect (same yoke BTW on both set of boards). The sound works without bypassing straight to the switching power supply and using only the transformer power like it should (same AR board BTW). Howefver the sound is very poor quality (sometimes crackly) and gets worse as you play (game warms up) compared to the other board set (which the sounds are perfect on the first set with the turbo issue, when I do the bypass power as mentioned above). Game runs better (except sound poor and gets worse as you play) on the donor board set, but the main SYS 1 board looks different than my first SYS 1 board.
Any ideas what could be the issue? Should I mix the boards and try to come up with a good working match?